Herbicidal alkylcarbamoyloxyphenyl biurets

ABSTRACT

ALKYLCARBAMOYLOXYPHENYL BIURETS SUCH AS 5-(3-(T-BUTYLCARBAMOYLOXY)PHENYL)-1,3-DIMETHYLBIURET AND 5-(3-(CYCLOHEXYLCARBAMOYLOXY)PHENYL)-3-EHTYL-1,1-DIMETHYLBIURET ARE USEFUL AS SELECTIVE HERBICIDES.

United States Patent O 3,567,764 HERBICIDAL ALKYLCARBAMOYLOXY- PHENYL BIURETS Richard K. Brantley, Westminster, Wilmington, DeL, as-

signor to E. I. du Pont de Nemours and Company,

Wilmington, Del.

No Drawing. Filed Apr. 12, 1968, Ser. No. 721,056 Int. Cl. C07c 127/24 US. Cl. 260-479 2 Claims ABSTRACT OF THE DISCLOSURE Alkylcarbamoyloxyphenyl biurets such as -[3-(t-butylcarbamoyloxy)phenyl]-1,3-dimethylbiuret and 5- [3-(cyclohexylcarbamoyloxy)phenyl] 3 ethyl 1,1 dimethylbiuret are useful as selective herbicides.

BACKGROUND OF THE INVENTION This invention relates to a novel class of alkylcarbamoyloxyphenyl biurets which are useful as herbicides. More particularly, the compounds of my invention when applied as hereinafter described, are useful as selective herbicides.

It is known that selected phenyl substituted biurets are herbicides. Representative biurets known to exhibit herbicidal activity are disclosed in US. Pat. No. 3,199,431 and Netherlands Pat. No. 6,503,645.

Such art, however, contains no suggestion that the novel alkylcarbamoyloxyphenyl biurets of my invention are selective herbicides.

SUMMARY OF THE INVENTION This invention relate-s to a novel class of alkylcarbamoyloxyphenyl biurets represented by the following formula:

where R is an alkyl of one through six carbons or cyclohexyl;

R is an alkyl of one through two carbons;

R is hydrogen, alkyl of one through two carbons or alkoxy of one through two carbons; and

R is hydrogen or an alkyl of one through two carbons.

This invention also relates to a method for the control of undesired plants which comprises applying an herbicidally effective amount of a compound of Formula I to the area to be protected. Preferably, the compound of Formula I is employed at a rate of application which is effective in selectively controlling undesirable plants, hereinafter called weeds, while causing no objectionable damage to desirable plants, hereinafter called crops.

This invention further relates to an herbicidal composition composed of an effective amount of a compound of Formula I in combination with suitable agricultural adjuvants and modifiers.

In a preferred embodiment of my invention as summarized above, 5-[3-(t-butylcarbamoyloxy)phenyl]-1,3- dimethylbiuret is employed as hereinafter described to control undesirable weeds in soybeans.

DESCRIPTION OF THE INVENTION The compounds of my invention can be viewed as consisting of a N-substituted carbamoyloxy functional group and a biureido functional group attached to a benzene ring. In general, methods for preparing each type of functional group and attaching such groups to a benzene ring are well known to the art. However, when preparing the Patented Mar. 2, 1971 PREPARATION It is most convenient to consider three general methods for preparing the compounds of my invention.

The first method is used to prepare those compounds of Formula I where R is described as above, R is hydrogen and R is the same as R; and each is an alkyl of one through two carbons. These compounds are readily prepared by the reaction of an m-alkylcarbamoyloxyaniline with the appropriate allophanyl chloride. The condensation of an appropriate allophanyl chloride with the aniline is usually carried out in a suitable solvent in the presence of an acid acceptor such as a tertiary amine. The desired allophanyl chloride is obtained by reacting phosgene with a 1,3-dimethyl urea or a 1,3-diethylurea.

The second method is used to prepare those compounds of Formula I where R is alkyl of one through six carbons or cyclohexyl and each of R R and R are alkyl of one through two carbons. These compounds are readily prepared by the reaction of a m-alkylcarbamoyloxyphenyl isocyanate with a suitably substituted urea. When this procedure is employed, care must be taken not to overheat the reaction system as undesirable rearrangements or decomposition can occur.

The remaining compounds can be readily prepared by the reaction of an appropriate allophanyl chloride with a suitably substituted amine.

The following examples are presented to further illustrate the preparation of the compounds of this invention. Parts and percentages are by weight in the following examples unless otherwise indicated.

Example 1 The procedure of Example 1 is repeated substituting 6 parts methylisocyanate for the t-butylisocyanate of Example 1 to produce m-nitrophenyl N-methylcarbamate, M.P. 130 C.

Examples 35 The procedure of Example 1 is repeated substituting an equivalent amount of the indicated Isocyanate for the t-butylisocyanate of Example 1 to produce the indicated Carbamate ester.

Isocyauate Carbamate ester Example:

3 Ethylisocyauate mNittrophenyl N-ethylcarbama e.

4 Isopropylisocyanatem-Nitrophenyl N-isopropylcarbamate.

5 Cyclohexylisocyanate... m-Nitropheuyl N-cyclohexylearbamate.

Example 6 Twenty parts m-nitrophenyl N-methylcarbamate is dissolved in parts ethyl acetate. To this solution is added 1.0 part 10% palladium on carbon catalyst. This mixture is agitated under a hydrogen atmosphere at a pressure of from 1 to 4 atmospheres until the absorbtion of hydrogen essentially stops. The catalyst is removed by filtration and the ethyl acetate is evaporated under reduced pressure.

The residue is m-aminophenyl N-methylcarbamate, M.P. 86-90 C.

When m-nitrophenyl N-t-butylcarbamate is reduced as described above, the product obtained is m-aminophenyl N-t-butylcarbamate, M.P. 9396 C. The desired maminophenylcarbamates can be obtained from the corresponding m-nitrophenylcarbamates using the method described in Example 6 above.

Example 7 4 dusts, solutions, granules, pellets, or high-strength compositions.

The surface-active agents, or surfactants, useful in the formulations of this invention act as wetting, dispersing and emulsifying agents which assist dispersion of the active material in the spray, and improve wetting of waxy foliage and the like by the spray. The surfactants can include such anionic, non-ionic and cationic agents as have been used heretofore in pesticidal compositions of similar type. A detailed list of such agents can be found in To a solution of 4 parts m-aminophenyl N-t-butylcar- 1O Detergents and Emulslfiers (John bamate in 40 parts tetrahydrofuran is added 3 parts tricutchleoll, ethylamine followed by 3 parts 1,3-dimethylallophanyl Anlonlc f P Surfactants are Preferred, chloride. The mixture is allowed to stand for 4 hours at Among the 311101110 Surfactants, Preferred Ones ijlre 311F311 about 25 C. and is poured into 200 parts water and 5-[3- I5 and alkaline earth Salts of alkylarylsulfomc golds (t-butylcarbamoyloxy)phenyl]-1,3-dimethylbiuret i col- Such as dodecylbenzenesulfonates and alkylnaphthalenelected. It can be purified by recrystallization from ethanol Sulfonatfis, y Sodlum Sulfosucclnate esters, sodfum and is found to melt at 1894900 lauryl sulfate, sodium N-methyl-N-oleoyltaurate, sodium dodecyldiphenyl ether disulfonate and the oleic acid Example 8 -10 ester of sodium isothionate. Among the non-ionic sur- Twelve parts anhydrous trimethylurea is heated slightly factants Preferred Ones include octylphenyl polyethylene above its melting point and one part m-t-butylcarbamoylglycol fibers dodecylptlenyl polyethylene glycol ethers oxyphenyl isocyanate is added The mixture is stirred polyoxyethylene derivatives of sorbrtan fatty esters and til homogeneous and the temperature is maintained for long'chaln alcohols and aptans, as well as polyoxyminutes. The mixture is then poured into 100 parts water ethylene esters, of fatty aclds' and 5 y y Y)p nyl]-3,1,1 n- Preferred drspersants are alkali and alkaline earth salts biuret is precipitated, collected, and purified by recrystalof hgnosulfomc acids salts of i x t, lization fonates which are sold under the Daxad and Darvan Example 9 trademarks, as well as methylcellulose, polyvinyl alcohol 30 and the like.

To a solution of 20.8 parts m-aminophenyl N-t-butyl- Surfactants are present in compositions of this incarbamate in 100 parts tetrahydrofuran is added a soluvention in amounts up to about by weight based on tion of 5.6 parts methyl isocyanate in 20 parts tetrahydrothe total weight of the resulting composition. When larger furan. The mixture is allowed to stand at about C. amounts of surfactant are desired, as for further improvefor four hours and is then poured into 400 parts ice water ment of contact activity, mixing in the spray tank is whereupon 1-[m-(t-butylcarbamoyloxy)phenyl]-3-methylusually preferable for convenience. urea is collected and thoroughly dried. Powder and dust preparations can be made by blend- A solution of 26.4 parts of the l-[m-(t-butylcarbamoyling the active ingredient, with or without surfactant, oxy)phenyl]-3-methylurea in 300 parts 1,2-dichlorowith finely divided solids such as talcs, natural clays, ethane is added to a solution of 15 parts phosgene in 200 pyrophyllite, diatomaceous earth; flours such as walnut parts 1,2-dichloroethane. A temperature of 0 C. is mainshell, wheat, redwood, soya bean and cotton seed; or tained during the addition and for one-half hour after inorganic substances such as magnesium carbonate, caladdition is completed. The solution is warmed slowly to cium carbonate, calcium phosphate, sulfur and lime. The 60 C. and a gentle stream of nitrogen is passed through compositions are made by thoroughly blending the active the solution until the evolution of hydrogen chloride has ingredient with the diluent and other additives. Usually essentially stopped. The solution is then evaporated to a grinding step, as in a hammer mill or fluid energy mill, dryness and y y y)P YU- is included. The particles in dust and powder preparamethyl allophanyl chloride is isolated from the residue. tions are preferably less than microns in average diameter. Examples 1043 5 Preferred wettable powder formulations will contain The procedure of Example 7 is repeated substituting 40% or more active ingredient together with sufficient equivalent amounts of the indicated Amine for the msurfactant and inert diluent to permit dispersion in water aminophenyl N-t-butylcarbamate of Example 7 and an for spray application. Compositions intended for dust equivalent amount of the indicated Allophonyl Chloride application will generally contain less than 50% active for the 1,3-dimethylallophonyl chloride of Example 7 to ingr dien obtain the indicated Product.

Amine Allophanyl chloride Product Example:

10 N ,O-din1ethylhydroxylamine 3-[m-(isnpropylearbamoyloxy) 6-[3-isopropylcarbamoyloxy)phenyl1- pllllfigiyl-l-methyl-allophanyl l-meth0xy-l,3-dimethylbiuret.

11 Ammonia 3-[ n1-(metliylcarba1noy1oxy)phenyl]- 5-[3-(methylcarbamoyloxymhenyl]-3- 1-etl1ylall0phanyl chloride. etliylbiuret.

12 N-methyl-N-ethylaminc 3-[m-(t-butylcarbamoyloxy)phenyl]- 5-[3-(t-bntylearbamoyloxypheuyH-ll-mcthylallophanyl chloride. ethyl-1,3-dimethylbiuret.

13 Diethylamine B-[m-(cyclohexylcarbamoyloxy) 5-[3-(cyclohexcarbamoyloxy)phenyllphenyll-l-methylallop hanyl chloride.

FORMULATIONS 1,1-diethyl-3-methylbiurct.

Powdered compositions can be converted to granules by adding moisture, treating mechanically and drying. Mechanical devices such as granulating pans, mixers and extruders can be used. Water soluble binders, such as inorganic salts, urea, ligninsulfonates, methyl cellulose, and the like, can be included in these particulate formulations in amounts up to about 25% by weight of the finished granule or pellet. Such materials also aid in disintegration of the pellet and release of the active ingredient under field conditions. Alternatively, a solution or suspension of the active ingredient can be sprayed on the surface of preformed granules of clay, vermiculite, corn cob and the like. Surfactants may also be included in formulations of the latter type.

Suspension formulations can be made in Water, or in organic solvents, or in mixtures of water and watermiscible organic solvents in which the active ingredient has a solubility under about 0.1%. The preparations can include, in addition to the active ingredient and liquid carrier, surfactants, viscosity control agents, anti-microbial agents and other modifiers. They are prepared by grinding the components in a sand mill or pebble mill preferably until the average particle size is under 20 microns. Water is the preferred liquid carrier. Hydrocarbon carriers should have boiling points above about 125 C. for safety in handling. Suspensions in hydrocarbons are suitable for extension in herbicidal or other spray oils and, by inclusion of a suitable emulsifying agent, can also be made sprayable from water.

The compounds of this invention are generally not sufficiently soluble in cheap, water immiscible solvents for economic use in emulsifiable concentrates. For particular purposes low strength emulsifiable mixtures can be made in the conventional way using chlorinated hydrocarbons, such as methylene chloride and chloroform, as solvents. Solutions in polar solvents such as dimethylformamide or dirnethyl sulfoxide can be used directly for low volume applications or extended with oil or other solvents.

All compositions intended for spray use can contain minor amounts of additives to reduce foam, inhibit corrosion, prevent claying, reduce caking, etc. as the conditions of use may dictate. The conditions of need for and use of such additives are generally known in the art.

Example 14 The following wettable powder is prepared.

Percent [3 (t butylcarbamoyloxy)phenyl] 1,3 di

methylbiuret 50 Dioctyl sodium sulfosuccinate 1.5 Sodium lignin sulfonate 3 Low viscosity methyl cellulose 1.5 Attapulgite Kaolinite 34 The ingredients are thoroughly blended, passed through an air mill, to produce an average particle size under microns, reblended, and sifted through a U.S.S. No. 50 sieve (0.3 mm. opening) before packaging.

A wettable powder containing 5-[3(t-butylcarbamoyloxy)phenyl]-1,l-dimethylbiuret as the active ingredient can also be prepared according to the method of Example 14.

Example 15 The following wettable powder is prepared.

Percent 5 [3 (methylcarbamoyloxy)phenyl] 1,1,3 trimethylbiuret 80 Sodium alkylnaphthalenesulfonate 2 Sodium ligninsulfonate 2 Synthetic amorphous silica 3 Kaolinite 13 The ingredients are thoroughly blended, passed through a hammer mill to produce an average particle size under 40 microns, reblended and sifted through a U.S.S. No. 50 sieve (0.3 mm. openings) before packaging.

Example 16 The following wettable powder is prepared.

Percent 5-[3 (cyclohexylcarbamoyloxy)phenyl] 3 ethyl-1, l-dimethylbiuret 65 Dodecylphenol polyethylene glycol ether 2 Sodium lignin sulfonate 4 Magnesium carbonate 6 Montmorillonite (calcined) 23 The ingredients are thoroughly blended. The liquid surfactant is added by spraying upon the solid ingredients in the blender. After grinding in a hammer mill to produce particles essentially all below 200 microns, the material is reblended and sifted through a U.S.S. No. 50 sieve (0.3 mm. opening) and packaged.

Example 17 The following high-strength concentrate is prepared.

Percent 5 [3 (isopropylcarbamoyloxy)phenyl] 1,3 dimethylbiuret 98.5 Silica aerogel 2 0.5 Synthetic amorphous fine silica 1.0

The ingredients are blended and ground in a hammer mlll to produce a high-strength concentrate essentially all passing U.S.S. No. 50 mesh. This material may then be shipped or formulated in a number of ways. For example, the following 25% dust can be prepared.

Percent High-strength concentrate 25.4 Pyrophyllite 74.6

The materials are thoroughly blended and packaged for use.

The ingredients are blended, hammer milled and moistened with about 12% water. The mixture is extruded as about 3 mm. diameter cylinders and cut as extruded to produce 3 mm. x 3 mm. pellets. These may be used as such after drying, or the dried pellets may be crushed to pass a U.S.S. No. 20 sieve (0.84 mm. openings). The fraction held on a U.S.S. No. 40 sieve (0.42 mm. opening) may be packaged for use and the fines recycled.

Example 19 The following granular formulation is prepared.

Percent Wettable powder of Example 15 15 Gypsum 69 Potassium sulfate 16 The ingredients are blended in a rotating mixer and water sprayed on to accomplish granulation. When most of the material has reached the desired range of 1.0 to 0.42 mm. (U.S.S. Nos. 1840), the granules are removed, dried and screened. Oversize material is crushed to produce additional material in the desired range. The granules contain 12% active ingredient.

Example 20 The following granular formulation is prepared.

I Percent Wettable powder of Example 15 10 Attapulgite clay granules (U.S.S. Nos. 20-40; 0.84-

An aqueous slurry of the wettable powder containing 50% solids is sprayed on the surface of warmed attapulgite granules in a V-blender. The granules are dried and packaged.

Example 2l The following solution is prepared.

Percent [3 (2 hexylcarbamoyloxy)phenyl]-3-methyl-lethylbiuret 25 Dimethyl sulfoxide 75 The ingredients are combined and stirred with warming to produce a solution suitable for low volume applications.

APPLICATION At application rates of 0.25 to 4 kilograms per hectare, the compounds of the present invention are useful for the selective control of weeds in crops such as soybeans, asparagus, sugarcane and pineapple. They may also be employed at rates of 2 to kilograms per hectare for the L long-term and complete control of any type of undesirable vegetation.

Example 22 The formulation of Example 14 is extended with sufficient water, while stirirng, to form a suspension containing 0.16 kg. of active per 100 liters. This Suspension is applied to a field of soybeans freshly planted in a silt loam soil at a rate of 300 liters per hectare. This treatment provides complete control of a mixture of weed species including crabgrass (lDigitaria spp.), giant foxtail (Setaria faberii), lambsquarter (C/zenopodium album) and smartweed (Polygonum pcnnsylvaniczmz), which heavily infests an untreated adjacent control plot. Weed control extends for a period of seven weeks after treatment. The treated area produces a highly satisfactory crop yield.

Example 23 The formulation of Example 15 is extended with water to produce a uniform suspension containing 5 kg. of formulation per 400 liters of liquid. The suspension is applied to a one-acre plot of ratoon sugarcane within 2 days after harvesting. The treatment results in excellent control of ragweed (Ambrosia trifida), goatweed (C roton Iindlzeimeri), crabgrass (Digitaria spp.) and Iohnsongrass (Sorghum halepense) for a period of 9 Weeks after application. The sugarcane, freed from weed competition, develops a good crop.

Example 24 The wettable powder formulation of Example 16 is extended with water to produce a uniform suspension containing 1 kg. of formulation per 40 liters of water. The suspension is applied at a rate of 800 liters per hectare early in the growing season to a mixed stand of weed species infesting an area around an oil storage tank. Included among the undesirable vegetation are weed species such as pigweed (Amarantlzus retroflexus), bromegrass (Bromus spp.), dogbane (Apocynum spp.), crabgrass (Digitaria spp.), plantain (Plantaga spp.), sheep sorrel (Rumex acetosclla), dandelion (Taraxacum ojficianale), spurge (Euplzorbia spp.) and barnyardgrass (Echinochloa crusgalli). Complete control of all vegetation is obtained throughout the duration of the growing season as a result of which fire hazards are greatly minimized.

Example 25 The dust formulation prepared as described in Example 17 is applied by means of a fertilizer spreader to a parking lot which normally is heavily infested with dandelion (Taraxacum ofiicianale), cinquefoil (Potentilla spp.), crabgrass (Digitaria spp.) and annual bluegrass (Poa anna). The dust is applied at the beginning of the growing season at a rate of 40 kg. per hectare. Good control of all 8 undesirable vegetation results for a period of 5 months after treatment.

Example 26 The pelletized formulation of Example 18 is manually applied at a rate of 20 kg. of formulation per hectare to an area at the foot of an advertising billboard which contains a vigorous stand of yellow foxtail (Setariu glauca), crabgrass (Digital-fa spp.) and blackeyed susan (Rudbeckia serotina). The application causes the weed growth to die within three weeks after application and the treated area remains bare of vegetation for a period of sixty-three days after treatment.

Example 27 The granular formulation of Example 19 is manually applied at a rate of kg. of formulation per hectare as a spot treatment to eradicate clumps of quackgrass (A gropyron repeus) scattered throughout a corn field. The chemical application kills both the corn and the quackgrass in the immediate area. The quackgrass dOes not recover and corn can be planted in the treated area the following year without suffering ill effects from the chemical.

Example 28 The granular formulation of Example 20 is applied by helicopter at a rate of 225 kg. of formulation per hectare to a forest firelane which is beginning to be reinfested with a mixture of weed species including green foxtail (Setaria viridis), bromegrass (Bromus spp.), red clover (Trifolinium pratense), milkweed (Asclepias spp.) and smartweed (Polygonlml rpp.). The treatment gives seasonal control of all vegetation in the treated area of the firelane and has only a transitory harmful effect on the bordering trees.

Example 29 The solution prepared as in Example 21 is extended with water to produce a liquid formulation which contains 1.5 kg. of active per 50 liters of water. The liquid formulation is uniformly applied by means of a bicycletype herbicide sprayer to a 1000 m. area of railroad ballast. The treatment causes the death of all weeds in the treated area within two weeks and prevents reinfestation of weed growth for an additional period of nine weeks. The weeds present at the time of treatment include young giant foxtail (Scmria faberii), crabgrass (Digilaria spp.) cocklebur (Xanthium spp.) and dropseed (Sporabalus rzeglectus).

R is alkyl of one through six carbons or cyclohexyl;

R is alkyl of one through two carbons;

R is hydrogen, alkyl of one through two carbons or alkoxy of one through two carbons; and

R is hydrogen or alkyl of one through two carbons.

2. 5-[3-(t-butylcarbamoyloxy)phenol] 1,3 dimethylbiuret.

References Cited UNITED STATES PATENTS 3,434,822 3/1969 Wilson et al. 260-479 JAMES A. PATTEN, Primary Examner US. Cl. X.R. 

